Study: Long Space flight May Damage Eyesight

It's true. A NASA sponsored study in Houston shows brain scans of astronauts who were in space for more than a month revealed potentially serious abnormalities that could force NASA to delay or even cancel plans for longer deep space missions.

Researchers at The University of Texas Medical School in Houston scanned the eyes and brains of 27 astronauts who had spent an average of 108 days in space, on space shuttle missions and aboard the International Space Station.

They found those who spent more than a month in space were more likely to suffer from intracranial hypertension -- which occurs when pressure builds within the skull.

The study found excess cerebral-spinal fluid around the optic nerve in 33 percent of the astronauts studied, while 20 percent showed a flattening of the back of the eyeball, which affects the ability to focus.

The scans also showed that 15 percent of the astronauts had a bulging optic nerve and 11 percent experienced changes to the pituitary gland, which is located between the optic nerves and secretes and stores hormones that regulate a variety of important body functions.

Professor Larry Kramer, lead author, says the findings revealed serious abnormalities in astronauts who were exposed to zero gravity for both short and long periods.

As for what this means for long space flights, Kramer says the impact of space travel on astronauts' brains and eyes presents a "potential limitation to long-duration space travel."

This is the latest finding in NASA's ongoing efforts to understand the effects of long duration space flight. Bone mineral loss and temporary muscular aches have been known to affect astronauts, and NASA is now focusing on concerns over astronauts' eye health.

Dr. William Tarver, chief of flight medicine at the Johnson Space Center, is skeptical, but says NASA has added potential eye damage to its list of human risks and will continue to monitor the situation.

Tarver describes the UT findings as "suspicious" but not conclusive of intracranial hypertension, and he adds that no astronauts have been considered ineligible for space flight duties as a result of the findings.

So far it appears that it's the absence of gravity that's causing most of the health problems some astronauts are experiencing. This underscores the need for space ships capable of creating artificial gravity for the people inside them. It can be done.